Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Testing a paleo diet hypothesis in the test tube

20.05.2014

By comparing how gut microbes from human vegetarians and grass-grazing baboons digest different diets, researchers have shown that ancestral human diets, so called "paleo" diets, did not necessarily result in better appetite suppression. The study, published in mBio® the online open-access journal of the American Society for Microbiology, reveals surprising relationships between diet and the release of hormones that suppress eating.

While Western diets have changed dramatically in the last century to become high energy, low fiber, and high fat (think: cheeseburger), our digestive systems, including our gut bacterial colonies, adapted over millennia to process a low-energy, nutrient-poor, and presumably high fiber diet. One idea about the current obesity epidemic is that appetite suppression systems that evolved to work with a paleo diet are off-kilter today.

The appetite-suppressing gut hormones peptide YY (PYY) and glucagon-like-peptide-1 (GLP-1) can be triggered by the presence of short-chain fatty acids (SCFAs) in the colon. Fermentation of plant fiber in the colon by bacteria can produce these SCFAs, so it stands to reason that digestion of a diet high in plant fiber might lead to better appetite suppression.

Gary Frost and his colleagues at Imperial College London in the United Kingdom wanted to test that hypothesis in the laboratory using fecal bacterial samples from three human vegetarian volunteers and from three gelada baboons, the only modern primate to eat mainly grasses.

"Getting to the bottom of how our gut bacteria and diets interact to control appetites is vitally important for tackling the problem of obesity," said Glenn Gibson, co-author on the study based at University of Reading. Frost added, "Understanding how a paleo-like diet impacts the colon's microbiota and the signals those bacteria produce to release hormones that reduce appetite may give us new insight that we can adapt in the modern world."

The team established gut bacteria cultures in flasks and then 'fed' them two different diets—either a predigested potato, high-starch diet or a predigested grass, high-fiber diet. Then they tracked changes in the numbers and types of bacteria and measured the metabolites produced by digestion.

Surprisingly, the human cultures on a potato diet produced the highest levels of SCFAs. Even the baboon cultures fed potato produced more SCFAs than the baboon cultures fed grass. When the researchers applied some of these cultures to mouse colon cells in the lab dish, the cells were stimulated to release PYY hormone. Those exposed to human cultures digesting a potato diet released the most PYY, followed by those exposed to baboon cultures on a potato diet.

This evidence argues that the previous view of paleo diets and appetite suppression is flawed and that high-fiber, plant-based diets likely do not lead to increased SCFAs and increased appetite suppression. Rather, the researchers propose, little to no appetite suppression might help baboons maintain grazing all day to consume enough nutrients.

A closer cataloguing of all the metabolites produced by the bacterial cultures digesting potato or grass diets showed that as the levels of the amino acids isoleucine and valine rose, so too did the amount of PYY released. This relationship was even stronger than that with SCFAs.

"This hints that protein might play a greater role in appetite suppression than the breakdown of starch or fiber," said Timothy Barraclough, another co-author of the study. "More work will be needed to explore the effects of alternative breakdown products of various foods."

The researchers note that this study of digestion in the test tube is limited by not including the roles of gut cells, which absorb and secrete metabolites as well.

###

mBio® is an open access online journal published by the American Society for Microbiology to make microbiology research broadly accessible. The focus of the journal is on rapid publication of cutting-edge research spanning the entire spectrum of microbiology and related fields. It can be found online at http://mbio.asm.org.

The American Society for Microbiology is the largest single life science society, composed of over 39,000 scientists and health professionals. ASM's mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.

Jim Sliwa | Eurek Alert!
Further information:
http://www.asmusa.org

Further reports about: SCFAs appetite baboons bacteria bacterial colon fiber grass metabolites microbiology potato suppression

More articles from Life Sciences:

nachricht How brains surrender to sleep
23.06.2017 | IMP - Forschungsinstitut für Molekulare Pathologie GmbH

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>